Recognised as Colour

#B21530

#B21530
Red
Dark
Nearest: Firebrick

#B21530 is a red with RGB values 178, 21, 48 and HSL 350°, 79%, 39%. It is a dark colour, so white text on it reaches 6.9:1 contrast (AA for normal text). The nearest named colour is Firebrick.

Colour values

#B21530#B21530

HEX#B21530

RGBrgb(178, 21, 48)

RGB (0–1)0.698, 0.0824, 0.1882

RGB percentages69.8%, 8.2%, 18.8%

HSLhsl(349.7, 78.9%, 39%)

HSV / HSBhsv(349.7, 88.2%, 69.8%)

CMYK0%, 88.2%, 73%, 30.2%≈naive device-independent conversion; real print needs an ICC profile

24-bit integer11,670,832

CSS custom property--colour: #B21530;

Brightness & contrast

Relative luminance0.10215WCAG 2.x, 0 is black and 1 is white

Perceived brightness100 of 255ITU-R BT.601 weighting

Light or darkDark

Best text colour on this backgroundWhitecontrast 6.9:1

Contrast with white6.9:1WCAG normal text: AA

Contrast with black3.04:1WCAG normal text: Fail

Greyscale equivalent#383838

Inverted#4DEACF

Colour vision & accessibility

Normal vision Protanopia Deuteranopia Tritanopia

Protanopia#4B4530no red cones; affects about 1% of men; ΔE 63.1 from the original

Deuteranopia#70652Bno green cones; the most common form, about 1% of men; ΔE 63.4 from the original

Tritanopia#C40022no blue cones; rare, and affects men and women equally; ΔE 14.4 from the original

Distinguishable without hueShifts in lightness toonever rely on hue alone to carry meaning

Contrast with white, large text6.9:1WCAG large text: AAA

Contrast with black, large text3.04:1WCAG large text: AA

Named colours

Firebrick · ΔE 10 Brown · ΔE 10 Crimson · ΔE 15.4 Dark red · ΔE 18.5 Maroon · ΔE 19.6 Indian red · ΔE 22

Nearest named CSS colourFirebrick (#B22222)ΔE 9.96, clearly different but related

Hue familyred

CSS keyword usableNo exact keyword

Colour harmonies

base +30°+90°+120°+180°+210°+240°+270°+330°

Complementary#15B297

Analogous#B2157F, #B24815

Triadic#30B215, #1530B2

Split complementary#15B248, #157FB2

Tetradic#7FB215, #15B297, #4815B2

Tints, shades & saturation

+40%+30%+20%+10%base -10%-20%-30%-40%

Lighter +40%#F49FAE

Lighter +30%#EE7287

Lighter +20%#E94460

Lighter +10%#E01A3C

Darker −10%#841024

Darker −20%#570A17

Darker −30%#29050B

Darker −40%#000000

More saturated +25%#C70022

Less saturated −25%#992E40

Channel breakdown

R178

G21

B48

Red178 (69.8%)

Green21 (8.2%)

Blue48 (18.8%)

Hue349.68°

Saturation (HSL)78.89%

Lightness39.02%

Dominant channelRed

Hex per channelR B2 · G 15 · B 30

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Harmonies

Lighter and darker

Similar named colours

Also reads as

B21530 (chemical formula)

Formula
232,739.3 g/mol
21530 atoms

B21530 has a molar mass of 232,739.3 g/mol, made up of 21530 atoms across 1 element: 21530 × B.

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Molar mass

Molar mass232,739.3 g/mol

Total atoms per molecule21530

Distinct elements1

Mass of one molecule3.864727 × 10^-19 g

Molecules per gram2.5875049 × 10^18

Name

NameNot in the name tablea name cannot be worked out from a formula alone: isomers share formulas, and naming depends on bonding the formula does not show

Composition by mass

B100%

Boron (B × 21530)232,739.3 g/mol, 100%

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Elements in this formula

Boron

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